Screw gauge



Feb. 1s, 1944. R'WILDERMUTH 2,341,679

SCREW GAUGE Filed Aug. 22. 1940 v A y so zo af 202 Patented Feb. 15,1944 UNlTED STTEE PATENT GFFICE SCREW GAUGE Richard Wildermuth,Stuttgart-Bad-Cannstatt,

Germany; vested in the Alien Property Custodian 1 Claim.

My invention relates to a thread gauge of the micro-meter caliper typehaving a stationary anvil and a displaceable member, the projectingpoints or tips of which are designed to engage the threads of a threadedbody to be measured.

It is an object of my invention to provide an improved instrument ofthis kind.

According to my invention the frame of the gauge carries, besides anexchangeable anvil member, which may be rigidly fixed to the frame, anda displaceable member, these two members being designed to engage in thethreads at di-ametrically opposite points, a graduated member (measuringbeam) operatively connected with the displaceable member and providedwith an exchangeable scale body, in the form of a thimble.

By providing the instrument with an exchangeable scale member I obtainthe advantage that various diameters and kinds of .threads can bemeasured with a single gauge, the exchangeable scale members enablingthe real measure or size as well as the allowed deviation (tolerance) tobe determined or measured.

In the drawing aiiixed to this specification and forming part thereof anembodiment of my invention is illustrated diagrammatically by way ofexample.

In the drawing Fig. 1 is a front elevation of an instrument according tothe invention, partly in section, while Fig. 2 is a plan view.

Fig. 3 shows the anvil drawn to a larger scale,

Fig. 4 is an end view of same,

Fig. 5 is a sectional view along line A-B of Fig. 2 drawn to a largerscale,

Fig. 6 is a similar section of a modied form,

Fig. 'I shows the thimble-shaped scale body.

Referring to the drawing, the instrument cornprises the frame I, thefixed'anvil member 2, the displaceable member 3 and socket 4 to whichthe frame I is fixed with the aid of the set screw 5. The frame Ifurther carries the supporting member 6 which is arranged for freedisplacement and can be iixed in position or adjusted by means of aclamping screw 1, and serves as support for the threaded work to bemeasured which is shown in Figs. 1 and 2 in dot and dash lines.

When the set screw 5 is loosened, the socket 4 arranged in frame I canbe displaced axially and adjusted and locked. In this socket 4 ismounted a bearing 8 for the displaceable member 3. This bearing 8 can be`displaced by means of the measuring member 9, which .cooperates with adevice which is arranged in the handle I0 and does not form a subjectmatter of the present invention.

On the measuring member 9 is arranged a scale body in the form of athimble I'I exchangeably mounted on a member I8 and locked thereon by acap screw.

The thimble II carries four scales. Three of these scales I9, 20 and 2|can be seen in Fig. 6, while the fourth scale 22 is situated on the rearside as shown in Fig. 6. To this end the thimble Il is formed with anumber of grooves 23, to

which a rigid key 24 is coordinated as guide member. The thimble II canbe removed when the cap screw I3 is unscrewed. If a different scaleshall be employed, the removed thimble I'I is turned through an angle ofor 180 and mounted on the member I8, with another groove 23 riding onthe key 24, whereupon the cap I3 is screwed down, so that the gauge isnow adjusted to a different scale.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

I claim:

In a thread gauge having a casing and a measuring member extendingwithin the casing and movable axially thereof, the combination whereinone end of said casing is provided with an axially extending cutawaypart whereby said end of the casing only partially surrounds themeasuring member, a scale carrier removably mounted on said measuringmember, one end of said carrier being engaged within said extension anda surface portion of the carrier being visible through said cutaway partin the casing when the carrier is in working position, cap meansremovably engaging the end of said measuring member adjacent the freeend of the carrier for retaining the carrier on the movable member whenthe carrier is in Working position, said carrier being positionable onthe measuring member in working positions wherein different portions onits surface are visible through said cutaway part in the casing, saidcarrier being provided with a plurality of separate axially extendinggrooves, and key means for engaging any desired groove when the carrieris mounted on said measuring member in a working position whereby toposition a selected surface portion of the carrier in alignment withthevcutaway part of the casing.

.Bh WILDERMUTH,

